A luminaire is a system for producing, controlling, and/or distributing light for illumination. For example, a luminaire can include a system that outputs or distributes light into an environment, thereby allowing certain items in that environment to be visible. Luminaires are often referred to as “light fixtures”. Conventional luminaires typically use conventional optical systems, including, a total internal reflection (“TIR”) lens, a hybrid optical system which includes a refractor and a reflector combination system, and/or a single reflector, for obtaining a desired light distribution. A conventional LED area light fixture is one type of luminaire that provides illumination for a broad area. For example, the light emitted from conventional LED area light fixtures is directed entirely around the fixture and illuminates a relatively broad area. A LED system consisting of numerous discrete LED chips is generally used in conventional LED area light fixtures so that sufficient light is available to illuminate the broad area.
Conventional LED area light fixtures typically are manufactured using numerous discrete LED chips that are bundled together to collectively produce a desired output. In one example, 288 discrete LED chips, having an optic positioned over each discrete LED chip, are bundled together to collectively produce a 300 W LED source for the conventional high power LED area light fixture. Discrete LED chips are small enough so that they are treated as a point source when designing the refractor and/or the reflector around each of the discrete LED chips. Thus, the design for the refractor and/or the reflector is easier for achieving desired light distributions than when non-point source LED types, such as a chip-on-board LED package having multiple LED chips mounted therein, are used. Although the optical design is easier when bundling discrete LED chips together to form conventional LED light fixtures, these conventional LED light fixtures are not very efficient, have a higher manufacturing cost due to the number of LEDs and optics that are used, and generate a significant amount of heat that is dissipated to the surrounding environment.
Chip-on-board LED packages allow for bright, uniform light output. These packages typically have a low thermal resistance which enables low junction temperatures at the chip level, thereby resulting in higher efficiencies. In a chip-on-board package, there typically are two junctions for each LED chip, namely between the chip to the substrate and the substrate to the heat sink. Fewer LEDs and optics are used when using chip-on-board LED packages than when using discrete LED chips, thereby reducing manufacturing costs. In one example, about eight to ten LED chips are positioned on a chip-on-board LED package to produce a 300 W LED source. Thus, cost savings are achievable if chip-on-board LED packages are used within LED area light fixtures. However, since the chip-on-board LED package has a relatively large area, it cannot be treated as a point source when designing the refractor and/or the reflector around each of the chip-on-board LED packages. Designing a refractor and/or to achieve desired light distributions has been very difficult, causing chip-on-board LED packages to not typically be used within LED area light fixtures.